This invention relates to a wheel brake mechanism for a bed and, more particularly, to a wheel supported patient supporting bed with a wheel brake mechanism thereon.
Wheel brake mechanisms are notoriously old as are wheel supported patient supports having a wheel brake mechanism thereon. The purpose performed by the wheel brake mechanism has heretofore been to prevent the wheels from rotating when locked as well as preventing castered wheels from castering. Not much importance was given to the situations where the wheel might move slightly or caster slightly when in the locked position. However, as uses for wheel supported patient supports has grown over the years, one particular use has developed in the surgical theater which mandates that the wheel supported patient support become fixedly located on its wheels and being free of slight rotational movements of the wheels as well as slight casterings of the castered wheels. The known wheel brakes have not provided satisfactory wheel locks that are acceptable to surgeons because of the impermissible slight movement of the patient support (or surgical table) during a surgical procedure. Accordingly, there exists a need to provide a solution to the aforesaid problem.
It is an object of this invention to provide a bed having a plurality of castered wheels thereon and a braking mechanism for fixedly locking the wheels in a secure manner so as to prevent rotation of the wheels about their respective axes of rotation and castering about their respective caster axes.
It is a further object of the invention to provide a bed, as aforesaid, which can be utilized to move hospitalized or assisted living patients from their room to a surgical site or other health care unit or therefrom to a recovery room, which wheels are fixedly positionable by a wheel braking mechanism so as to permit a use of the bed in a surgical or other type of patient care environment.
It is a further object of the invention to provide a bed having a force multiplying mechanism actuatable by a conventional brake pedal wherein an attendant may apply the brakes to the wheels supporting the bed with minimal force to effect a secure positioning of the bed in a desired location.
It is a further object of the invention to provide a bed, as aforesaid, having four castered wheels thereon and wherein the wheel braking mechanism simultaneously controls the locking and unlocking of the aforesaid four castered and rotatable wheels.
It is a further object of the invention to provide a bed, as aforesaid, wherein the wheel brake activating mechanism can also be used to deploy an auxiliary fifth wheel which, when in the deployed position, facilitates steering the wheel supported bed during movements thereof in a direction parallel to the longitudinal axis thereof.
It is a further object of the invention to provide a brake mechanism for a wheel supported bed which is easy to maintain and easy to operate.
The objects and purposes of the invention are met by providing a bed with a wheel brake. The wheel brake includes a crank arm mounted on a frame of the bed and movable between first and second positions about a first axis of rotation. An elongate first link is pivotally connected at one end to a first pivot joint provided on the distal end of the aforesaid crank arm. An elongate second link is pivotally secured to the bed frame for movement about a second axis of rotation between third and fourth positions and is pivotally secured on one side of the second axis of rotation to the first link by a second pivot joint oriented a finite distance from the aforesaid first pivot joint. A wheel engaging brake member is swingably suspended from the bed frame and above an outer periphery of a wheel rotatably and swivelably supported on the bed frame and for movement into and out of engagement with the aforesaid outer periphery. An elastically yieldable resilient member and an elongate third link are interconnected between the wheel engaging brake and the second link for effecting a continuous urging of the third link toward the second link when the crank arm is in the second position and the first pivot joint is oriented on a side of a center position remote from a side caused by the crank arm being in the aforesaid first position so that the wheel engaging brake is swung into engagement with the outer periphery of the wheel in response to the crank arm moving from the first position to the second position and the resilient member yielding to permit the first pivot joint to move from one side to an opposite side of the center position, the resilient member effecting a holding of the wheel engaging brake in engagement with the aforesaid outer periphery of the wheel.